(chocolateyGH-1040) use lower case for uninstall / log more

When uninstalling packages, attempt to use lower case as the local file
system could be having issues finding the package. Log more surrounding
what is going on to try to pinpoint the source of the issue. Also skip
removing files if they are already deleted.

src/chocolatey/infrastructure.app/services/NugetService.cs

@@ -1061,8 +1061,11 @@ private void remove_shim_directors(ChocolateyConfiguration config, IPackage inst
 
         private void remove_cache_for_package(ChocolateyConfiguration config, IPackage installedPackage)
         {
+            this.Log().Debug(ChocolateyLoggers.Verbose, "Ensuring removal of package cache files.");
             var cacheDirectory = _fileSystem.combine_paths(config.CacheLocation, installedPackage.Id, installedPackage.Version.to_string());
 
+            if (!_fileSystem.directory_exists(cacheDirectory)) return;
+
             FaultTolerance.try_catch_with_logging_exception(
                                        () => _fileSystem.delete_directory_if_exists(cacheDirectory, recursive: true),
                                        "Unable to removed cached files");
@@ -1326,7 +1329,7 @@ public ConcurrentDictionary<string, PackageResult> uninstall_run(ChocolateyConfi
                                 rename_legacy_package_version(config, packageVersion, pkgInfo);
                                 remove_rollback_directory_if_exists(packageName);
                                 backup_existing_version(config, packageVersion, pkgInfo);
-                                packageManager.UninstallPackage(packageVersion.Id, forceRemove: config.Force, removeDependencies: config.ForceDependencies, version: packageVersion.Version);
+                                packageManager.UninstallPackage(packageVersion.Id.to_lower(), forceRemove: config.Force, removeDependencies: config.ForceDependencies, version: packageVersion.Version);
                                 ensure_nupkg_is_removed(packageVersion, pkgInfo);
                                 remove_installation_files(packageVersion, pkgInfo);
                                 remove_cache_for_package(config, packageVersion);
@@ -1366,12 +1369,15 @@ public ConcurrentDictionary<string, PackageResult> uninstall_run(ChocolateyConfi
         /// <param name="pkgInfo">The package information.</param>
         private void ensure_nupkg_is_removed(IPackage removedPackage, ChocolateyPackageInformation pkgInfo)
         {
+            this.Log().Debug(ChocolateyLoggers.Verbose, "Removing nupkg if it still exists.");
             var isSideBySide = pkgInfo != null && pkgInfo.IsSideBySide;
 
             var nupkgFile = "{0}{1}.nupkg".format_with(removedPackage.Id, isSideBySide ? "." + removedPackage.Version.to_string() : string.Empty);
             var installDir = _fileSystem.combine_paths(ApplicationParameters.PackagesLocation, "{0}{1}".format_with(removedPackage.Id, isSideBySide ? "." + removedPackage.Version.to_string() : string.Empty));
             var nupkg = _fileSystem.combine_paths(installDir, nupkgFile);
 
+            if (!_fileSystem.file_exists(nupkg)) return;
+
             FaultTolerance.try_catch_with_logging_exception(
                 () => _fileSystem.delete_file(nupkg),
                 "Error deleting nupkg file",
@@ -1380,6 +1386,7 @@ private void ensure_nupkg_is_removed(IPackage removedPackage, ChocolateyPackageI
 
         public void remove_installation_files(IPackage removedPackage, ChocolateyPackageInformation pkgInfo)
         {
+            this.Log().Debug(ChocolateyLoggers.Verbose, "Ensuring removal of installation files.");
             var isSideBySide = pkgInfo != null && pkgInfo.IsSideBySide;
             var installDir = _fileSystem.combine_paths(ApplicationParameters.PackagesLocation, "{0}{1}".format_with(removedPackage.Id, isSideBySide ? "." + removedPackage.Version.to_string() : string.Empty));
 
@@ -1392,6 +1399,8 @@ public void remove_installation_files(IPackage removedPackage, ChocolateyPackage
 
                     if (fileSnapshot.Checksum == _filesService.get_package_file(file).Checksum)
                     {
+                        if (!_fileSystem.file_exists(file)) continue;
+
                         FaultTolerance.try_catch_with_logging_exception(
                             () => _fileSystem.delete_file(file),
                             "Error deleting file");